Test for Evaluation of Cream

Table of Contents

1. Uniformity of weight

2. Sterility (For Sterile cream)

3. Irritancy study

Mark an area of 1 sq.cm on the left hand dorsal surface. The cream was applied to the specified area and time was noted. Irritancy, erythema, edema was checked, if any, for regular intervals up to 24hrs and reported.

4. Determination of pH

Measured by a standard digital pH meter at room temperature.

5. Physical appearance

Observed by its colour, roughness and graded.

6. Spreadability

Adequate amount of sample is taken between two glass slides and a weight of 100gm is applied on the slides for 5 minutes. Spreadability can be expressed as,

S= m*l/t

Where, m = weight applied to upper slide.

l = length moved on the glass slide.

t = time taken

7. Saponification value & Acid value (If oily base is used)

Saponification value: 2gm of substance refluxed with 25ml of 0.5 N alcoholic KOH for 30 min, to this 1ml of phenolphthalein added and titrated immediately, with 0.5N HCl, note the reading as ‘a’. Repeat the operation omitting the substance being examined. Note the reading as ‘b’

Saponification value = (b-a)*28.05/w
Where,
w = weight of substance in gram.

Acid value: 10gm of substance is dissolved in accurately weighed 50 ml mixture of equal volume of alcohol and solvent ether, the flask was connected to reflux condenser and slowly heated, until sample was dissolved completely, to this 1ml of phenolphthalein added and titrated with 0.1N NaOH, until faintly pink colour appears after shaking for 30 seconds.

Acid value = n*5.61/w

Where,
n = the no. of ml of 0.1 N KOH solution.
w = the weight of substance in gram.